A device which emits light to an earhole portion of a user so as to measure pulses of the user based on reflected light has been known.
For example, a device in one example of the background art includes a PPG measurement module which detects light conveyed from the skin in the earhole and outputs a PPG signal containing biological information. The PPG measurement module includes a light source unit which emits light to the skin in the earhole and a light detection unit which detects light emitted from the light source unit and reflected by the skin in the earhole. A PPG signal processing unit includes a pulse detection unit which measures pulses by detecting a peak of a PPG signal and calculating a time interval between peaks.